Chapter: Monitoring IP and MPLS Multicast Configurations

Monitoring IP and MPLS Multicast Configurations

IP Multicast is a bandwidth-conserving technology that reduces traffic by simultaneously delivering a single stream of information to thousands of corporate recipients and homes. Applications that take advantage of multicast include video conferences, corporate communications, distance learning, and distribution of software, stock quotes, and news.

IP Multicast delivers source traffic to multiple receivers without adding any additional burden on the source or the receivers while using the least network bandwidth of any competing technology. Multicast packets are replicated in the network by Cisco routers enabled with Protocol Independent Multicast (PIM), Multicast Label Distribution Protocol (MLDP) and other supporting multicast protocols resulting in the most efficient delivery of data to multiple receivers possible.

Multicast is based on the concept of a group. An arbitrary group of receivers expresses an interest in receiving a particular data stream. This group does not have any physical or geographical boundaries—the hosts can be located anywhere on the Internet. Hosts that are interested in receiving data flowing to a particular group must join the group using Internet Group Management Protocol (IGMP). Hosts must be a member of the group to receive the data stream.

For information on the devices that support IP and multicast, refer to
Cisco Prime Network 4.1 Supported VNEs
.

These topics provide an overview of the IP Multicast technology and describe how to view IP and multicast configurations using the Vision client. If you cannot perform an operation that is described in these topics, you may not have sufficient permissions; see Permissions for Managing IP and MPLS Multicast.

Routing entities. If you have configured multicast route information for a VRF, the Vision client displays a separate tab for the related VRF wherein you can view the multicast routing information. See Viewing Routing Entitiesand Viewing VRF Properties.

Viewing Multicast Nodes

To view the Multicast node:

Step 1 Right-click on the required device and choose the Inventory option.

Step 2 In the Inventory window, choose Logical Inventory > Multicast. The Route Policies and Multicast Global Interfaces tabs are displayed in the content pane as show in Figure 23-1. You can click on the tabs to view more details.

Figure 23-1 Multicast Content Pane

Table 23-1 describes the fields that are displayed in the Route Policies tab.

Table 23-2 describes the fields that are displayed in the Address Family (IPV4) profile.

Table 23-2 Address Family (IPV4) Profile

Field Name

Description

MDT Source Interface

The source interface to set the multicast VPN data.

Note This interface can identify the root of the MDT in the service provider network. This interface and its corresponding address is used to update all Multicast VPN (MVPN) peers through multiprotocol Border Gateway Protocol (BGP).

MDT Static

The interface used for transporting MDT data.

Interface All

Indicates whether the multicast routing and protocols are enabled on the interfaces.

Note You must enable the interfaces using the Interface command in the multicast-routing configuration mode.

NSF Status

Indicates whether the non-stop forwarding capability is enabled for all the relevant components.

Note If this feature is enabled, then multicast forwarding will not stop on failure of the control plane multicast routing components.

Note This interface can identify the root of the MDT in the service provider network. This interface and its corresponding address is used to update all Multicast VPN (MVPN) peers through multiprotocol Border Gateway Protocol (BGP).

Viewing the IGMP Profile

The IGMP runs between hosts and their immediately neighboring multicast routers. The mechanisms of the protocol allow a host to inform its local router that it wishes to receive transmissions addressed to a specific multicast group. Also, routers periodically query the LAN to determine if known group members are still active. If there is more than one router on the LAN performing IP multicasting, one of the routers is elected querier and assumes the responsibility of querying the LAN for group members. Based on the group membership information learned from the IGMP, a router is able to determine which (if any) multicast traffic needs to be forwarded to each of its leaf sub networks. Multicast routers use this information, in conjunction with a multicast routing protocol, to support IP multicasting across the Internet.

There are three versions of IGMP:

IGMP Version 1

IGMP Version 2

IGMP Version 3

To view the IGMP profile:

Step 1 Right-click on the required device and choose the Inventory option.

Step 2 In the Inventory window, choose Logical Inventory > Multicast > IGMP. The IGMP details are displayed in the content pane. You can click on the tabs to view more details.

Table 23-4 describes the fields that are displayed in the IGMP profile.

Table 23-4 IGMP Profile Details

Field Name

Description

NSF Status

The non-stop forwarding status, which can be Normal or Non-Stop Forwarding Activated.

Note The Non-Stop Forwarding Activated status implies that recovery of an IGMP failure is in progress.

Interfaces Tab

Interface Name

The name of the interface.

Associated Entity

The link to the associated entity, which when clicked will highlight the associated Default routing entity record under the Routing Entity node.

Interface Address

The internet address of the interface.

VRF

The VRF to which the interface belongs. This is a link, which when clicked will take you to the relevant record under the VRF node.

IGMP Status

Indicates whether IGMP is enabled or disabled on the interface.

IGMP Version

The IGMP version installed on the interface.

Groups Tab

Group Address

The address of the multicast group.

Interface Name

The name of the interface used to reach the group.

Associated Entity

The associated entity for the IGMP profile. Click this link to view the related record under the Subscriber Access Point node.

VRF

The VPN Routing and Forwarding (VRF) to which the interface belongs. This is a link, which when clicked will take you to the relevant record under the VRF node.

Up Time

The period from when the multicast group is available. This information is displayed in terms of hours, minutes, and seconds.

Expires

The duration after which the multicast group will be removed from the IGMP groups table. This information is displayed in terms of hours, minutes, and seconds.

Last Reporter

The most recent host that has reported being a member of the multicast group.

Group Ranges Tab

Group Range

The multicast group range in CDIR format, which is basically the Multicast Group IP address followed by the CDIR prefix.

Protocol

The PIM protocol that is used by the IGMP group range.

Viewing the PIM Profile

PIM is a family of multicast routing protocols for Internet Protocol (IP) networks that provide one-to-many and many-to-many distribution of data over a LAN, WAN or the Internet. It is termed protocol-independent because PIM does not include its own topology discovery mechanism, but instead uses routing information supplied by other traditional routing protocols such as the Routing Information Protocol, Open Shortest Path First, Border Gateway Protocol and Multicast Source Discovery Protocol. There are four variants of PIM:

PIM Sparse Mode (PIM-SM)

PIM Dense Mode (PIM-DM)

Bidirectional PIM

PIM source-specific multicast (PIM-SSM)

Although PIM is called a multicast routing protocol, it actually uses the unicast routing table to perform the Reverse Path Forwarding (RPF) check function instead of building up a completely unrelated multicast routing table. PIM does not send and receive multicast routing updates between routers like other routing protocols.

To view the PIM profile:

Step 1 Right-click on the required device and choose the Inventory option.

Step 2 In the Inventory window, choose Logical Inventory > Multicast > PIM. The profile details are displayed in the content pane. You can click on the tabs to view more details.

Table 23-5 describes the fields that are displayed in the PIM profile.

Table 23-5 PIM Profile Details

Field Name

Description

NSF Status

The non-stop forwarding status, which can be Normal or Non-Stop Forwarding Activated.

Note The Non-Stop Forwarding Activated status implies that recovery of an IGMP failure is in progress.

Interfaces Tab

Interface Name

The name or ID of the interface on which PIM is enabled.

Associated Entity

The link to the associated entity, which when clicked will highlight the associated Default routing entity record under the Routing Entity node.

IP Address

The IP address of the interface.

VRF

The name of the VRF associated to the interface. This is a link, which when clicked will take you to the relevant record under the VRF node.

PIM Status

Indicates whether the PIM is enabled (ON) or disabled (OFF) on the interface.

Hello Interval

The frequency at which PIM hello messages are sent over the PIM enabled interfaces.

These messages are sent at regular intervals by routers on all the PIM enabled interfaces. The router sends these messages to advertise their existence as a PIM router on the subnet.

Designated Router

The IP address of the designated router on the LAN.

Note Serial 4.3.2 do not have a designated router. Hence, the IP address is displayed as 0.0.0.0. If the interface on the router is the designated router, then the words “This system” is displayed. If not, then the IP address of the external neighbor is displayed.

Designated Router Priority

The priority of the designated router, which is advertised by the neighbor in the hello messages. This value in this field will range from 0 to 4294967295.

Rendezvous Points Tab

RP Address

The address of the interface serving as a rendezvous point for the group range or list.

A Rendezvous Point (RP) is a router in a multicast network domain that acts as a shared root for a multicast shared tree. Any number of routers can be configured to work as RPs and they can be configured to cover different group ranges. For correct operation, every multicast router within a Protocol Independent Multicast (PIM) domain must be able to map a particular multicast group address to the same RP.

Mode

The PIM protocol mode for which the router is advertised as a rendezvous point. The mode can be PIM-SM or bidirectional PIM.

Scope

The number of candidate announcement messages sent out from the rendezvous point.

Priority

The value of the candidate rendezvous point priority.

Uptime

The amount of time from when the rendezvous point is available.

Group List

The IP access list number or name of the group prefixes that are advertised in association with the rendezvous point address.

RP Type

The type of rendezvous point, which can be BSR or Auto RP.

Note The Bootstrap Router (BSR) is a mechanism for a router to learn RP information. It ensures that all routers in the PIM domain have the same RP cache as the BSR. Auto-RP is a mechanism to automate distribution of RP information in a multicast network. The Auto-RP mechanism operates using two basic components, the candidate RPs and the RP mapping agents.

Topology Tab

Source Address

The IP address of the source of the multicast entry. In case the IP address is not available, a “*” or 0.0.0.0 is displayed here.

Group Address

The multicast group address or prefix for which the entry is associated with.

PIM Mode

The PIM mode of the topology entry, which can be Sparse, Source Specific, Dense, or Bidirectional.

Tree Type

The MDT tree type for the route entry, which can be Shortest Path Tree or Rendezvous Point Tree.

Uptime

The amount of time from which the topology is available. This value is displayed in terms of seconds.

RP Address

The Rendezvous Point address. This value is displayed only if the PIM Mode is SM or Bidirectional.

Join Prune Status

Indicates whether a join or prune message is sent to the RPF neighbor for the route.

RPF

The IP address and interface ID, along with the MoFFR information, of the Reverse Path Forwarding for the topology.

Flags

The comma separated flag information for this topology.

Neighbors Tab

Neighbor IP Address

The IP address of the neighbor.

Interface Name

The interface name on which the neighbor can be reached.

Associated Entity

The link to the associated entity, which when clicked will highlight the associated Default routing entity record under the Routing Entity node.

VRF

The name of the VRF.

Flags

The flags that provide information about various states of the neighbor.

Designated Router Priority

The priority of the PIM interface for DR election. The default value is 1.